The use of what is known as "two-up" sheet material has become very common in the sheet material arts. Prior art, two-up sheet material, as shown in FIG. 1, comprises a long continuous web of sheet material onto which the subject matter for separate pages 2 are printed side-by-side on the web. While FIG. 1 shows the two-up material wrapped around and formed into a roll, it is equally plausible that the two-up material can be fan-folded.
Typically, this long web with the side-by-side printing will be provided to an end-user for further processing. Such further processing will typically include separating each of the pages from the rest of the web so that various operations such as collecting, accumulating, and folding can be carried out prior to sending the sheets to a downstream inserter machine. This separating part of the further processing is shown in FIGS. 2A, 2B.
As shown in FIG. 2A, the continuous web material 1 is fed downstream in the feed direction symbolized by arrow F. Continuous web material 1 is then slit down its center axis, thereby forming side-by-side webs 1a, 1b separated by slit S. The slitting step can be carried out by an overhead slitter blade 15 supported by a shaft 10 or any other type of slitter since the mechanism used for the slitting is not critical to the instant invention.
After the slitting step, as shown in FIG. 2B, a blade 30 of some type is used to cross-cut the two side-by-side webs 1a, 1b, across their transverse axes. This cross-cut totally separates sheets 20a and 20b from the two side-by-side webs 1a, 1b. The action of blade 30 is repeated and therefore two side-by-side streams of sheet material are then formed and fed to a downstream operation such as an accumulator, collector, or folder.
It is typically desired that these two side-by-side streams be merged into a single stream because most downstream operations cannot handle doublewide sheet material. Accordingly, methods of merging side-by-side streams have been implemented. For example, in U.S. Pat. No. 5,362,039 to Kusters, assigned to Bell & Howell GmbH, multiple such methods are shown in FIG. 3. A problem with the Kusters method, however, is that the orientation of the sheets is changed during the merging. That is, not only is the sheet path turned 90.degree., but the sheets are also flipped over. As can be appreciated by those of skill in the art, there are applications, however, in which this change of orientation is undesirable.
Accordingly, there is room for improvement within the art.